Low density water blown spray rigid polyurethane foam is primarily used in commercial and residential areas where spraying polyurethane foam brings advantages such as heat and sound insulation as well as mechanical integrity. Such foams should advantageously have low amine emissions.
The conventional methods for making this type of foam with densities of approximately 8 Kg/m3 use blowing amine catalysts such as bis-(dimethylaminoethyl)ether (BDMAEE) or pentamethyldiethylenetriamine (PMDETA). These amines are characterized by their high vapor pressure and strong amine odor. Thus, amine exposure can occur during system blend preparation, spraying and final use (occupancy).
Gelling catalysts are typically tertiary amines characterized in that they have higher selectivity for catalyzing the urethane reaction to the blowing or urea reaction. These catalysts are expected to perform poorly in systems containing high concentrations of water because of their inability to activate water towards isocyanate.